Subsea hot tapping involves creating a new branch of an existing pressurized subsea flowline. This is done by locating the position on the existing line where the hole will be created, installing a pressure containment collar, drilling a hole in the line, removing the coupon, and connecting the new line to the old one. Subsea hot tapping has been a very complex and expensive operation, involving bulky and massive apparatus and collars.
U.S. Pat. No. 6,648,562 discloses an apparatus for tapping a hole in a pipeline adapted to be attached to a support assembly having sealed communication with the exterior of a pipeline and having a tapping machine body with a boring bar rotatably supported therein with a circular cutter at the lower end thereof, a feed screw rotatably supported by the tapping machine body for axially positioning the boring bar, a hydraulically powered boring bar drive assembly within the tapping machine body driving the boring bar, a hydraulically powered feed screw drive assembly within the tapping machine body driving the feed screw and an auxiliary drive shaft affixed to rotate the feed screw drive assembly extending exteriorly of the tapping machine body and adapted to receive supplementary mechanical rotary energy for rotation of the feed screw so the boring bar can be retracted if hydraulic power is lost. A pressure compensation system permits the apparatus to be operated in a subsea environment. A position indicating system permits the location of the boring bar to be read out at a remote location, such as on the ocean's surface and an improved coupon retainer is provided. U.S. Pat. No. 6,648,562 is herein incorporated by reference in its entirety.
U.S. Pat. No. 6,290,432 discloses a diverless process of tapping a pressurized subsea pipeline without removing the pipeline from service. The process includes the steps of lowering and landing a measurement tool onto the pipeline in order to check ovality and straightness of the pipeline with the measurement tool. Pipe lift frames are lowered and landed onto the pipeline spaced from a chosen location. The pipeline is lifted by hydraulic actuators or mechanical screws on the lift frames. A hot tap fitting and accompanying orientation frame are lowered and landed on the pipeline between the pipe lift frames. The pipe lift frames are incrementally raised until the pipeline is fully seated in the hot tap fitting and orientation frame. A fitting clamp is secured to the pipeline. A hot tap machine is lowered onto the hot tap fitting and orientation frame. The pipeline is then tapped with the hot tap machine. The pipeline is thereafter lowered by deflating the lift frame bags. U.S. Pat. No. 6,290,432 is herein incorporated by reference in its entirety.
There is a need in the art for improved hot tapping systems and methods.
There is a need in the art for less massive hot tapping systems.
There is a need in the art for less complex hot tapping systems.
There is a need in the art for hot tapping systems with a lower power requirement.
There is a need in the art for hot tapping systems that can be maneuvered and/or operated with an ROV (remotely operated vehicle).
There is a need in the art for less expensive hot tapping systems and methods.